The invention relates to a display device, and more particularly to a switching device for a pixel electrode and methods for fabricating the same.
Bottom-gate type thin film transistors (TFTs) are widely used for thin film transistor liquid crystal displays (TFT-LCDs). FIG. 1 is a sectional view of a conventional bottom-gate type TFT structure 100. The TFT structure 100 typically comprises a glass substrate 110, a gate 120, a gate-insulating layer 130, a channel layer 140, an ohmic contact layer 150, a source 160 and a drain 170.
As the size of TFT-LCD panels increases, metals having low resistance are required. For example, gate lines employ low resistance metals such as Cu and Cu alloy in order to improve operation of the TFT-LCD.
However, Cu can react with radicals to form Cu oxide in subsequent processes, thereby increasing resistance. Also, Cu diffuses easily and reacts with silicon to form CuSix, significantly affecting reliability of the device.
JP 2000-332015, the entirety of which is hereby incorporated by reference, discloses a method of forming CuSix. A layer of CuSix is formed between a silicon-rich nitride layer and a Cu layer, enhancing adhesion therebetween.